The Science of the Long Run (Read 1759 times)

Correct. I'm not saying there's a training benefit, except possibly a mental boost, but I don't see where the harm is either. Everyone always says, if you can run 10 then you can do a half, or if you can run 20, then you can do a full. If those extra miles are no problem on race day, then they shouldn't be a problem at least once during training, right?

OK, sorry, I misunderstood. I read it as you were going to do a 26 mile long run again this summer in training for a fall marathon. You've already done the 26.2 run before starting training.

and I've seen many posts suggesting one shouldn't run more than 2:30-3:00 hours on a long run. That won't take the slow marathoners anywhere near the distance of the race or even that "magic" 20-miles. At the low mileage many of them run I don't see how they can adequately prepare for the distance with that methodology.

Physiologically, I don't believe anyone needs to nor should they be running more than 3 hour long runs for marathon training. BUT, your statement above nailed it - "At the low mileage many of them run, I don't see how they can adequately prepare for the distance with that methodology".

Many marathoners go into a marathon unprepared because of low mileage. The long run is important no doubt, but the other 6 days of the week are more important. Higher miles during the week are crucial to build strength and make you a stronger and a more efficient runner. The problem occurs with the training plans set up by marathon organizers is that the emphasis is the long run. Most everyone runs that long run at a pace they plan on running the marathon. That long runs beats the heck out of them. The reason why is not only length of time on feet but there is not enough miles during the week to support a very long duration long run. More miles during the week makes you more resilient and better able to recover from these 3-4-5 hour + long runs which is too much anyway.

I know the question comes up around confidence and mental hurdles. All I would say is that the human body is very resilient. Most of us regular runners can do a marathon today even without specific training if the goal is to finish. It may not be pretty but you can do it. Undertrained or inexperienced marathoners are the ones that are mentally weak. When I work with runners, I make sure they are prepared. I would not coach a person wanting to do a marathon if not already running 20 plus miles a week for at least 6-12 months. Then give me another 6 months to prepare them. All the time I am asked to help someone who has done no running for months but wants to do a marathon in 4-5 months. I refuse to beat up and get my friends injured. I tell them to sign up for a 10K or perhaps a half first and come talk to me in 6 months. I am just not a fan of cramming in marathon training, doing it and then saying you did it. My feeling is, if you are going to do it, do it the right way and this will make you physiologically and mentally stronger to handle the task.

I believe your antecedent is false, wrecking the syllogism (if that is the correct word).

That is to say, the race day effort is not comparable to a training run -- at least, it takes many runners many extra days to full recover from the race day effort - often more days than they spent recovering from any training run.

I think that one of the criticisms of a 26 mile training run is that it beats you up and requires extra recovery -- my point is that a marathon raced also tends to beat up the race and require extra recovery -- even *more so*. So I think that your argument (people do it on race day) isn't a good counter to the argument that such a long run costs too much recovery time.

That was only a critique of the logic there. I'm not arguing against running 26 miles in training. Some people do that. (I myself, in fact. But I don't advocate that others do it - it depends on your goals, and how your body handles recovery, I think.)

I can definitely understand that from a recovery standpoint. I tend to recovery fairly quickly. I ran my 26.25 miles on day 18 of my current streak, with no rest or tapering, and was fully recovered (zero lingering soreness/affects) three days after the run, while running all three of those days (I do better with active recovery). I would venture to guess that most beginners can't recover like that from a 26 mile run.

OK, sorry, I misunderstood. I read it as you were going to do a 26 mile long run again this summer in training for a fall marathon. You've already done the 26.2 run before starting training.

Well, knowing me, I'd say there's a good chance I'll do it again before running my first full. But as I said, it's more for the mental boost than any possible training benefit. I will say tho that for the rest of my training for my upcoming half, I will keep my long run to 16-18 miles max, while also incorporating speed work (I keep saying that, need to actually start doing it lol).

I don't know where you got that from my comment and question. I asked the question because the impression I've gotten when posters say the body only knows duration, not distance, is that covering specific distances in training for the marathon is not necessary, that all you need to do is train by duration - and I've seen many posts suggesting one shouldn't run more than 2:30-3:00 hours on a long run. That won't take the slow marathoners anywhere near the distance of the race or even that "magic" 20-miles. At the low mileage many of them run I don't see how they can adequately prepare for the distance with that methodology.

In any case your following explanation was what I was hoping to see.

Your post:

"When race day comes the runner has a set distance to run, not a set duration."

Your body does not know distance, only effort and duration. Yet you are defending training slower marathon runners just like runners going nearly twice as fast.

Most (most) 50-mile racers do not run 40 miles in training. I'm not sure I know any 100-mile racer who runs an 80-miler in training. Ultra runners understand that you can get all you need to get through a 5-6 hour race without having to approach the actual distance in training. The same applies to slower marathon runners who are moving at a pace at or even slower than their typical training pace.

Additionally, the runners you are wanting to see to 20-milers in training....those probably doing 20-40mpw in training...are also those worst prepared to actually execute and...more importantly benefit from...20-milers. When you have to spend several days resting for, then several days recovering from, one of these 20-milers what training benefit are you getting from it? You're giving up so much and putting it all in that one run. That is exactly why the Hanson's plan caps long runs at 16 miles....this prevents newer runners from getting caught up in over-emphasizing the long run and pounding themselves up with them, sacrificing consistency and volume throughout the rest of the week.

"If you want to be a bad a$s, then do what a bad a$s does. There's your pep talk for today. Go Run." -- Slo_Hand

"When race day comes the runner has a set distance to run, not a set duration."

Your body does not know distance, only effort and duration. Yet you are defending training slower marathon runners just like runners going nearly twice as fast.

Most (most) 50-mile racers do not run 40 miles in training. I'm not sure I know any 100-mile racer who runs an 80-miler in training. Ultra runners understand that you can get all you need to get through a 5-6 hour race without having to approach the actual distance in training. The same applies to slower marathon runners who are moving at a pace at or even slower than their typical training pace.

Additionally, the runners you are wanting to see to 20-milers in training....those probably doing 20-40mpw in training...are also those worst prepared to actually execute and...more importantly benefit from...20-milers. When you have to spend several days resting for, then several days recovering from, one of these 20-milers what training benefit are you getting from it? You're giving up so much and putting it all in that one run. That is exactly why the Hanson's plan caps long runs at 16 miles....this prevents newer runners from getting caught up in over-emphasizing the long run and pounding themselves up with them, sacrificing consistency and volume throughout the rest of the week.

I'm not defending them. I think the obsession with 20-mile runs is ridiculous. What I don't see is how training by duration, then limiting that duration to 2.5-3 hours could possibly get slower runners ready for a marathon. I think you're confusing my query about how should they train then, with sanctioning an approach I think is faulty. I'm a strong critic of the standard beginners marathon program for many of the reasons you've cited. Personally I wouldn't run a marathon unless I'd been consistently logging 50 mpw for 4-6 months, but lower that in my recommendations to 40 mpw - with the LR not exceeding 30% of weekly mileage as a starting point for marathon training, even for a first timer.

I've seen this statement and variations on it again and again from very respected posters, but I still don't see the sense in it. Maybe it makes sense from a physiological response with mitochrondia and capillaries, but what about from calorie expenditure and work performed. When race day comes the runner has a set distance to run, not a set duration. How do you translate that to training for the slower runner? I think Nobby made a reference at one point that slower runners need to train more like ultra runners, but I'd love to see more elaboration on that and input from others.

I think Spaniel explained it quite well.

Here's what Nobby said: "For a slower runner, a marathon becomes an ultra event, being on their feet for over 4, 5, 6 hours."

If I may go on a slight tangent: I read in "Daniel's Running Formula" the following: "I think that tow hours a day of running is quite a lot, and it's unusual for even elite runners to run more than three hours a day", then he states "Remember that stress is a function of time spent doing something and that's why a 20-mile run is more stressful for a slow runner than for a faster one. It's not the 20 miles but the time spent completing those 20 miles. The increased number of steps can wear you down, and th extra hour in the heat or on slick roads can take its toll. To avoid overtraining injury, slower runners might have to run less total mileage than faster runners". (Taken from page 92).

Later he states on page 98, under the "Long Runs" heading: "Less-talented, less-fit, or less-experienced runners shouldn't necessarily set a specific distance for their L-run goal because they stand a greater chance of overstressing themselves". Then he asks the rhetorical question, "Runs of three hours or more aren't popular for elite runners, so why should less experienced runners try them?"

Now, I don't recall where Daniels stated that a long run of 2.5 hours should be your max, but that's typically the absolute max he presents in his training plans. I think he stated that the physiological benefits aren't that great once you get past 2.5 hours, but I may be wrong. He stated that ultra-runners would benefit from runs longer than 23 miles, but marathoners (and below) would probably not benefit from them (in the physiological sense).

OK, long set-up for my tangent: because of these max times while training, and because I'm rather slow, I've taken the position that my maximum race distance is the half-marathon. I did run a marathon once (it sucked), but I found that the half-marathon is a distance that I can handle, and more importantly, the training associated with it doesn't drain the life out of me both in terms of time and energy. I'm not saying others should follow my advice, and if they'd like to run a marathon at slow speeds, that's fine. But that's an ultra-like experience compared to the faster runners (and I think that's part of Nobby's point).

I’d like to make a couple of quick observations/comments regarding this forum topic.

1. fellrnr provided a great service to us all by starting the topic off. Regardless of what you feel about the quality of his post, or the validity, the discussion that it generated is top notch.

2. I’ve have only heard mention of nobby before, always with respect. Now I understand. I don’t know him, but it is obvious this is someone who has spent many years in our chosen sport at many levels. I truly appreciate the time he has taken to share some of his thoughts and experience.

3. Fellrnr also posted this topic on RW. At last check a total of 6 members responded, and none to the degree we have seen here. I’m glad I found RA and have moved my lurking here.

I'm not defending them. I think the obsession with 20-mile runs is ridiculous. What I don't see is how training by duration, then limiting that duration to 2.5-3 hours could possibly get slower runners ready for a marathon. I think you're confusing my query about how should they train then, with sanctioning an approach I think is faulty. I'm a strong critic of the standard beginners marathon program for many of the reasons you've cited. Personally I wouldn't run a marathon unless I'd been consistently logging 50 mpw for 4-6 months, but lower that in my recommendations to 40 mpw - with the LR not exceeding 30% of weekly mileage as a starting point for marathon training, even for a first timer.

Slower runners training by duration frequently will NOT limit their long runs to 2.5 to 3 hrs. This is where many of the discussions come from. I also believe that many beginner marathon programs are faulty but because they build too fast in the 2nd half of the program. There's no way I would have capped my long run at 3 hrs for a 5-6 hr race when I was starting. Then again, I'm not sure anyone had suggested that in the first few years I was running. My e-mentor is an ultrarunner.

Look at how many ultrarunners do long runs of 4-8 hrs with no major issues. Most don't do them every week unless they're doing races every week and the race is the long run. Yes, they've built up to them over time, usually. Yes, there's a lot of hiking in there, esp. on the uphills. Which means there's a lot of downhill running also with those impacts. There is lots of variation in how the muscles are being used. From my minimal experience, the wear and tear is from the downhills with a pack (we don't have aid stations). I, personally, wouldn't do a 2.5-3hr long run on flat asphalt - too repetitive and I have mental lapses (that's me, something about aptitude for certain things), but I can handle multiple hours on hills, even with most of it asphalt (early in season when I'm building on road to ski area before the trails become snow free).

I definitely agree that unless you've built up to them, longer long runs can make a runner more vulnerable to overuse injury.

The people that are requiring multiple days of recovery may not be adequately trained to handle long runs of that duration.They should spend more time building up. The problem, IMHO, is the preparation level, not the duration of the long run.

It also depends what you consider "recovery". I generally do an easy run on flats or hike rolling hills the day after a 6-8 hr long run - or maybe reverse, depending on what life has been serving up. I generally run 2 days on / 1 off, but the "off" day may be hiking or trail work - or it may be nothing - effectively giving me 5 days or more of something. Flat, fast stuff on grass will usually come a few days after the long run - recovery from the downhills. Then my 3 other key workouts in a microcycle return to either rolling hills or big hills, which are preparing me for the long run with 3000-4000 ft of up and down usually (when I'm in the final stages of prep, about 2 months out). The long long runs are only every 2 wks since I use a 2-wk microcycle (approximately). (My life schedule tends to be random with minimal notice of some meetings, so days between long runs may vary between 12 and 15 days.)

I'll admit that I'm not familiar with how others around here train other than seeing the ultra runners (on FB) in the mountains all the time running or hiking with their dogs, frequently for multiple hours.

As already mentioned, I think there's a huge difference between run/hiking on trails in the mountains vs constant running on flat asphalt.

"So many people get stuck in the routine of life that their dreams waste away. This is about living the dream." - Cave Dog

I'm not defending them. I think the obsession with 20-mile runs is ridiculous. What I don't see is how training by duration, then limiting that duration to 2.5-3 hours could possibly get slower runners ready for a marathon. I think you're confusing my query about how should they train then, with sanctioning an approach I think is faulty. I'm a strong critic of the standard beginners marathon program for many of the reasons you've cited. Personally I wouldn't run a marathon unless I'd been consistently logging 50 mpw for 4-6 months, but lower that in my recommendations to 40 mpw - with the LR not exceeding 30% of weekly mileage as a starting point for marathon training, even for a first timer.

If the bolded part is really your question, I already gave you quite a concise answer, I'm not sure how to put it any better. If you don't believe me, why don't you wait until our friends running the Desert Solstice 24-Hour race how they completed up to nearly 160 miles over 24 hours without ever doing more than maybe a quarter that time/distance during a "long run". Training is not predicated simply on trying to replicate what you will do on race day. It's using a multi-faceted approach to create the adaptations with will get you through race day...and adding volume throughout the week to make you stronger will get a slower marathoner through a marathon better than beating themselves up with overly long long runs every week or two and then only doing a few other token overly SHORT runs throughout the rest of the week.

The rest of this post I cannot understand. Honestly this is the second thread in which you seem to start with one question and when people give replies you change the question. I don't mean this to sound harsh but I am trying to understand and answer. You think the obsession with 20 mile runs is ridiculous, but you are arguing that they need to run roughly that in duration (you are not happy with only 3 hour long runs, so if a 5 hour marathoner is doing a 4 hour run that's around 20 miles). And now as you argue for runs >>3hrs for slow marathoners to prepare them, you want them doing 40mpw with a long run of 30% that volume....roughly 13 miles? None of this seems consistent. Even if that is just the starting point, to get them to the kind of long runs you are arguing for they are going to be at 50% of their miles for the week in the long run. That doesn't leave much for balanced training.

"If you want to be a bad a$s, then do what a bad a$s does. There's your pep talk for today. Go Run." -- Slo_Hand

Perhaps in the spirit of full disclosure it might be appropriate for those of us discussing the "long run" to state just how many long runs we've done in the past 52 weeks. That might add a bit of validity to our comments. I, for instance, have had 8 @ 16 to 18, 5 @ 18 to 20, and 5 over 20 (including 2 marathons). I'm sure that many training for marathons put these numbers to shame. But if all you have is, say for instance, one run of 10 miles, then I'm not sure what you can really add to this discussion, or why you would even want to be involved.

...What I don't see is how training by duration, then limiting that duration to 2.5-3 hours could possibly get slower runners ready for a marathon...

George:

We have a saying in Japanese (I'm changing slightly): "We can't beat IRS and crying babies." There are certain things that are so inevitable that you cannot wing it.

I've been corresponding with Toshi Takaoka, a 2:06:16 marathon runner who recently had been appointed to be the head of distance running division for Japan Federation. We talk a lot about how to bring Japanese marathoning more competitive internationally. One of the things we've talked about recently is not to think marathon as a special event compared to 5k or 10k. Far too many "competitors" look at a marathon as some sort of monster, creating some kind of mental barrier and that won't help. However, that said, for beginning runners it IS something special. When we created Running Wizard--and when I say "we", I mean me, Lorraine Moller and Dick Brown--, we sat down and we dissected, turned it upside down and analyze it, portion by portion...trying to "standardize" the formula. One of the challenges that we had was preparation for a marathon. At first, we just simply used the same formula, as Lydiard had, for 1500m, 5k or 10k or a half marathon. Two things we spent more time trying to figure out the consensus among us was long run for marathon and duration of Beginner's Plans. At first, I wanted to have one 3-hour run. But that seemed too much for faster guys. We went on and on and on until Dick said, "What's so special about 3-hour run? Why do we have to have that?" We couldn't come up with any legit reason. So we settled for 2:30, with the longest suggested range being 2:45 (that means, if you really want to, you can go as long as 2:45). That seemed enough especially with the fact that you'll go on and on with near-longest run for several weeks that follow--"it's the total volume of the run and not just single super effort that matters." Now, the beginner's plan was another matter. We felt, even up to a half marathon, if you really wanted to, you could probably get ready for it in 12-weeks. Even if you are starting out at 15 or 20 minutes max today, if you follow a systematic program, you can most probably "survive" a 13-miler after 12-weeks of systematic build-up. We couldn't really see it possible with a full marathon. In the end, IF you can run up to 90-minutes right now, you CAN manage to get ready to run a full marathon in 12-week period. But if your current level is about an hour max, we'd prefer you to take MINIMUM of 17 weeks to build-up. If you're a beginner, and the level or more like 20 or 30 minutes, then it'll extend to 32-39 weeks. This is because of this "inevitable" things--that it takes longer to develop your endurance; unlike speed, which brings us to yet another heated topic of WHEN you'll need to start working on "speed" which, it seems, many argue that you'll need to start working on speed RIGHT AWAY if you want to run faster. This is wrong. Speed can be developed fairly quickly. But endurance takes a long time to develop. In order to develop enough endurance to go the full marathon distance, we felt that 12-weeks is not enough. Is 32 weeks enough? Well, when Lydiard took up those 20 obese business people back in 1961, they couldn't even run around a HALF of a lap around the local high school track (200m). Eight months later (32 weeks), they were running 20-miles WITHOUT STOPPING and 8 of them ran a full marathon....in around 4-hours. So we knew it could be done.

So going back to your original question; how can you expect for someone to prepare for a marathon, a full marathon, when the long run is mere 12 or 13 miles? Well, the total distance run will be calculated as: total duration in minutes divided by pace (minutes-per-mile). Or total duration in minutes ÷ pace in minutes-per-mile (I just wanted to see if the math symbol works!). If the total duration is set, the faster you train, the further you can run within the set duration of time. I firmly believe that the whole problem, and this vicious cycle, started when people decided to stay at plodding speed. They never work on speed, they never work on form, ALL they care about the distance covered. We encourage BALANCE in training; we have slower runs, we have faster runs, we have sprint workout... Hills will strengthen your legs and makes you enable to run faster easier. We would still need to collect more statistics and evidence but, if you balance your training correctly, I really don't think people would be plodding along at 14-minute mile pace. If you run 10-minute-per-mile pace, then you can cover 15-miles in 2:30. 15 ain't too bad to prepare for a marathon. Again, I don't know if any "research" had been conducted but I'd be very curious to see coaches' opinion, and I think we see this often here at RA threads, that total volume of training per week may be even more important than one big effort. For example, if you cover, say, 55MPW with the long run being 15-miler, would you be better prepared to run a full marathon than, say, someone who "only" runs 35MPW with the long run being 20??? Or, if you "only" run your long run as a 12-miler, if you do it every weekend for, say, 8 weeks, like Waitz or Salazar had done, would you be well-prepared enough to challenge a full marathon distance??? Right now, with my own anecdotal examples is something like n=8, but it seems EVERY SINGLE ONE OF THEM seem to point out that it would. Someone would always come back and say; "Well, I did 4 X 20-miler and I did fine..." Well, fine. Define "fine" then? My "anecdotal" examples seem to hobble around 3:15-3:40 range. One, which I like to mention all the time although so far just this one person, improved his 5:30 PR down to 4:50 by cutting back all those 20-milers.

Rod Dixon came to our clinic in September last year in Boulder. We talked about these things and, only a week after our talk, he called me and asked me about this "shorter long run" plan. He was working with LA Road Runners Club to prepare them for LA marathon in March. He said the original plan had 4 X 20-miler. I told him that it's absolutely too much. For a psychological reason (as someone else had mentioned), he kept ONE 20-miler but he dropped down the others to 16-miler. A week after LA marathon this spring, he texted me and said that the finish rate went up from 70% to 95% and injury rate went down from 25% to 5% (something like that--I can't remember the exact numbers). It's not a matter of numbers (16-miles) but the Hanson's book makes perfect sense to us because we had been doing that all along and it seems to have worked.

... And now as you argue for runs >>3hrs for slow marathoners to prepare them, you want them doing 40mpw with a long run of 30% that volume....roughly 13 miles? None of this seems consistent. Even if that is just the starting point, to get them to the kind of long runs you are arguing for they are going to be at 50% of their miles for the week in the long run. That doesn't leave much for balanced training.

If you look at a 6-8 hr long run every 2 wks for someone who is averaging 9-10 hr/wk, that's about 30-40% of that 2-wk microcycle. (Nothing magic about 7 days, and I think Hansons use 10 days.) The individual weeks might be 8 and 12 hr or whatever, but it's balanced across the microcycle. I know you're quoting wcrunner, who I think is trying to understand the way training by duration and intensity works.

In my own case, I do recognize that total distance / duration doesn't need to be covered, but I also believe that there are training adaptations for runs beyond 4 hr. Figuring out fuel, hydration, electrolytes, gear if nothing else, but also the endocrine system (don't have a citation for it).

"So many people get stuck in the routine of life that their dreams waste away. This is about living the dream." - Cave Dog

In my own case, I do recognize that total distance / duration doesn't need to be covered, but I also believe that there are training adaptations for runs beyond 4 hr. Figuring out fuel, hydration, electrolytes, gear if nothing else, but also the endocrine system (don't have a citation for it).

Yes, but you are thinking more towards ultras....and it sounds like fairly difficult ones with regards to terrain. Personally, in prepping for a 50-miler, I am trying to get in one 4-hour run per month. But that effort sort of makes the point -- despite all the volume I have, there is something with my pelvis and back that starts to fall apart right around 4 hours. If all the mileage I've run and years experience I have still leave me liable to injury with 4-hour runs, why would I recommend them to newer/slower/less trained runners?

"If you want to be a bad a$s, then do what a bad a$s does. There's your pep talk for today. Go Run." -- Slo_Hand

Yes, but you are thinking more towards ultras....and it sounds like fairly difficult ones with regards to terrain. Personally, in prepping for a 50-miler, I am trying to get in one 4-hour run per month. But that effort sort of makes the point -- despite all the volume I have, there is something with my pelvis and back that starts to fall apart right around 4 hours. If all the mileage I've run and years experience I have still leave me liable to injury with 4-hour runs, why would I recommend them to newer/slower/less trained runners?

Correct about the ultras, and just did first marathon this year (at age 65 but only about 10 yr of running, after having done one 50mi and 50k previously, and a few 38mi partials). Just a thought, but have all those years and miles of pounding on asphalt (?) left you with some vulnerabilities? (I remember you from usenet back when you were going for OTQ and trained so hard. We were all rooting for you.) Just in following some of the newer competitive ultrarunners (the 20 somethings), they seem to break onto the scene with a big splash, and a couple years later are known more for being injured.

When I was new, I had AT, PF (both issues before I started running more consistently), then some hip problems (too much mountain too soon), but a PT helped me strengthen feet and ankles and I had a xt class that helped with core, etc. Most of my running is on trails with lots of variation in muscle movement. I'm just not seeing that sort of breakdown in myself or others around me - or they hide it well. OTOH, maybe those have retired from running (my GP who used to run had hip replaced and only mtn bikes and xc skis now). I'm just saying that different people have different strengths and weaknesses. An occasional person starts with 100-mi races - they just seem to have an aptitude for longer events and training.

Yes, the first time at a duration / distance is challenging, but one adapts to it over time. And I don't recommend being somewhat prepared for a 3-hr run, misplacing the trail, and doing close to 4 hrs on packed snow as one's first 4-hr run. But a few days later, it wasn't all that bad - but chose not to exceed 4 hr the next time until I adapted.

But, yes, I can understand your concern.

"So many people get stuck in the routine of life that their dreams waste away. This is about living the dream." - Cave Dog

. Just a thought, but have all those years and miles of pounding on asphalt (?) left you with some vulnerabilities? (I remember you from usenet back when you were going for OTQ and trained so hard. We were all rooting for you.) Just in following some of the newer competitive ultrarunners (the 20 somethings), they seem to break onto the scene with a big splash, and a couple years later are known more for being injured.

Apologies to all for following off on a tangent here but....

Yes, I am sure I've developed some liabilities over time and some of it may be related to how hard I pushed it in prior years. I think more of it has to do with the fact that I don't have easy access to a variety of terrain (and time) to keep all of my core muscles properly in balance. I'm trying to be better about doing planks etc to try and make up for some of this -- the first time I did it, it was obvious that I had some imbalances in strength and I think that over a very long run as I get tired this is what does me in.

Some of the newer competitive ultrarunners that I THINK you are referring to are former road runners too, I speculate that part of their problem is that they try to take it to a high level at these new distances before they have conditioned their bodies to handle the particular challenges of trail running over races that long.

"If you want to be a bad a$s, then do what a bad a$s does. There's your pep talk for today. Go Run." -- Slo_Hand